The Knot Weed is a very ornamental plant for any garden because the foliage is so beautifully tinted in Autumn. Some of the varieties grow very high and greatly resemble Bamboo in growth. Polygonum sochalinense is one of this type, attaining a height of from 2 feet to 12, feet, with leaves 12 inches long and sprays of greenish-white flowers. The stems are curving or arched. P. acne (Brunonis) is the dwarf variety, growing 6 inches to 18 inches high, with bright, rosy red flowers and beautifully colored foliage. P. amplexicaule grows about 2 feet or 3 feet tall and has deep red flowers which come into bloom very late in September and last until October. P. Sieboldii compactum grows about 15 inches high, has small, glossy green leaves, and the entire plant is covered with small white flowers. Most of the varieties are in bloom from July through August.
UTILIZE. The Giant Knot-Weed is used mostly in wild gardens or under trees, wherein immense shrubby perennial is needed. The other varieties are grown in front of shrubs or herbaceous borders. Some of the dwarf ones are used in rockeries. Any of these are very effective when planted in masses, especially along banks of streams or in moist places. Some of the flowers are valued for cutting.
GENERAL. Some Polygonumsrequire a great deal of space, for the plants are very large. They are moisture-loving and should be planted in places where the ground is naturally very moist and does not dry out easily. They will grow almost anywhere, in any soil, and need very little attention.
PROPAGATION. They are propagated by seeds and division of the plant.
Polygonum – Knot-Grass, Knot-Weed